gpio: Merge TCA6416 & TCA6408 drivers into TCA64XX

This merges TCA6416, TCA6408 drivers and adds PCA9555 support.
They handle 8 pin and 16 pin ICs with basic INPUT/OUTPUT functionality.
The register map is fairly similar so there is no point in having two
separate drivers.

Reviewed by: kd
Obtained from: Semihalf
Differential Revision: https://reviews.freebsd.org/D36559

Add driver for marvell, a37x0 peripheral clocks

Add driver for Marvell, Armada-37xx peripheral clock.
Register clocks for various peripheral devices in
north bridge or south bridge domain. Dump clock's
domain while verbose boot.

Reviewed by:
Obtained from: Semihalf
Differential revision: https://reviews.freebsd.org/D32294

Add driver for armada, 37x0-tbg-clock

Driver for tbg clocks. Read reference frequency from parent
and modify it depending on parameters read from register.

Reviewed by: manu
Obtained from: Semihalf
Differential revision: https://reviews.freebsd.org/D32293

Add driver for marvell, armada-3700 oscillator

Driver registers new clock device. Clock frequency is set depending
on tenth bit's value obtained from syscon register. Full information
about the clock is dumped if bootverbose is enabled.

Driver was tested on EspressoBin.

Reviewed by: manu
Obtained from: Semihalf
Differential revision: https://reviews.freebsd.org/D32292

e6000sw: Build the driver as a kernel module

Fix detach routine.
Driver was tested on EspressoBin.
Remove it from GENERIC, since now it can be loaded automatically.

Obtained from: Semihalf
Reviewed by: manu
Differential revision: https://reviews.freebsd.org/D31580

arm64: Add per SoC family kernel config

There is multiple reason for this :
- This makes it easier to see which driver is needed for each SoC
- This makes it easier to create a custom config for one SoC
- This really reduce boot time (which some people might want)

Some explaination about the files :
- std.arm64 contains all standard kernel option
- std.dev contains all the standard kernel devices
- std.<soc> contains all drivers needed to boot on this SoC family
- <SOC> includes std.arm64, std.dev and std.<soc>
- GENERIC includes std.arm64, std.dev and all std.<soc>

Sponsored by: Diablotin Systems
MFC After: 2 months
Reviewed by: mmel, cognet, imp
Differential Revision: https://reviews.freebsd.org/D30474